Abstract
In Fukushima decommissioning, to predict the distribution of boron species in the fuel debris is important because it affects the risk of re-criticality. Thus, the eutectic melting and relocation behavior of boron carbide (B4C) control rod materials receive remarkable attention. Our recent experiment dynamically visualized the behavior of the eutectic melt, but it stayed in the original location even after the melting. However, mechanism for the no relocation was not clarified. In the current study, the behavior of the eutectic melt was analyzed by the simple eutectic model based on the moving particle semi-implicit (MPS) method. The obtained results indicated that the no relocation in the experiment may be explained by the isothermal solidification of the eutectic melt due to the diffusion of the boron.
